The present invention relates to bicycle steering lock, and in particular, to a key locking mechanism which pins the steering shaft so that the bicycle cannot be steered while the pin is in position.
Various locking mechanisms are known which employ a pin through the steering shaft to lock the steering shaft so that the bicycle cannot be steered, thus discouraging theft or tampering. For example, U.S. Pat. No. 3,863,472 to Klingfus discloses a bicycle locking device which may be manufactured as part of the original equipment of the bicycle or may be added on at a later date. The device is mounted to the tubular head portion of the bicycle with a circular mounting ring. The circular mounting ring has a rear facing body portion with a key operated locking mechanism. There is an opening through which a spring operated plunger is released or withdrawn by the key mechanism. The plunger passes through the opening in the tubular head and engages one of a number of apertures in the steering wheel post. The Klingfus device does not operate with an inner and an outer plunger and does not employ ball bearings received in a receptacle to lock the plunger into place. Furthermore, the Klingfus device does not employ a retractable plunger and lock mechanism which may be removed from the bicycle entirely.
U.S. Pat. No. 777,854 to Hirschenfeld discloses a combination type of bicycle steering lock which uses a pin which passes through the steering fork shaft so that the steering wheel cannot be turned. The lock mechanism is a combination lock with a series of rotating rings which have slots in the inner sides. The pin has a series of projections which are able to pass through the slots when the rotating rings are in the proper positions, but which prevent the pin from being withdrawn when the rings are rotated out of the proper positions. Hirschenfeld does not disclose an inner and outer pin arrangement, nor the use of a ball and pin receptacle to lock the pin in place. Hirschenfeld has an integral key and pin mechanism.
U.S. Pat. No. 4,232,537 to Plaiss discloses a bicycle lock which uses a standard cylinder type lock mechanism. In the Plaiss device the cylinder lock mechanism operates a crank type linkage with an attached pin which may be inserted into or withdrawn from an opening in the steering wheel fork. In addition to the pin the lock mechanism also operates a bar which locks over rings attached to a rope for anchoring the bicycle to a metal post or rack. Plaiss does not employ an inner and outer pin arrangement or ball bearings to lock the pin in position.
The limitations of the prior art are overcome by the present invention as described below.